This invention relates to an engine induction system and more particularly to a high performance compact engine induction system particularly adapted for use with V type engines.
It has been recently acknowledged that the performance of an internal combustion engine can be significantly improved by providing a compound induction system for each cylinder of the engine wherein there is provided a relatively short intake passage that is tuned for good high speed performance and a relatively long intake passage that is tuned for low speed performance. In order to fully optimize the advantages of such an arrangement and provide a relatively compact assembly, it has also been proposed to provide a pair of plenum chambers, each of which supplies air to a respective one of the intake passages at its inlet end. This type of induction system has particular utility with V type engines wherein each of the plenum chambers can be positioned above a respective one of the cylinder banks. An induction system of this general type is shown in U.S. Pat. No. 4,649,876, entitled "Intake Means Of Internal Combustion Engine", issued Mar. 17, 1987 in the names of Masatoshi Ohmi et al and assigned to the assignee of this application.
This type of induction system is particularly effective in providing good performance throughout the entire engine load and speed ranges without sacrificing performance under any running condition. However, the complexity of the induction system can give rise to certain difficulties in connection with vehicles wherein engine height is critical. That is, in the type of induction system shown in U.S. Pat. No. 4,649,876 can give rise to a significant increase in the height of the engine even though the system is relatively compact.
It is, therefore, a principal object of this invention to provide an improved high performance type of induction system wherein each cylinder of the engine is served by both long low speed runners and short high speed runners and wherein the induction system nevertheless is extremely compact.
It is a further object of this invention to provide an improved compact induction system for an internal combustion engine.
It is a further object of this invention to provide an induction system for a V type internal combustion engine that employs separate plenum chambers and pairs of intake passages for each cylinder of the engine served respectively by the plenum chambers that is compact and yet does not sacrifice performance.